I can now summarize the overall argument. First, the short version. The 22% patch and the 28% patch look different when foveated and attended one after the other. However, fixating in between them and attending to the 22% patch, they look the same. How can this be explained representationally without supposing that the precision of attentive foveal vision is narrower than that of inattentive peripheral vision? As before, this is a burden of proof argument that does not explicitly utilize the idea of phenomenal precision.
And as before, here is the long version:
The attended 22% patch and the unattended 28% patch, being the same in contrast-phenomenology are the same in contrast-representational contents.
Both are veridical.
The contrast attributed by vision to the two patches has a minimum span of 22%-28%.
Attended and foveal percepts of 22% and 28% (seen sequentially) are determinately different in phenomenology.
Phenomenal precision principle: the phenomenal precision of the percepts of the patches seen attended and foveally is narrower than the phenomenal precision of at least one of the percepts seen in the periphery with only one attended. And it is plausible to suppose it is the unattended percept that has the wider precision.
So the phenomenal precision of the attended foveal percepts must be narrower than at least one of the peripheral percepts (probably the unattended one).
Representationism requires that a difference in phenomenal precision be grounded in a commensurate difference in representational precision.
So representationism requires that the precision of the foveal attended percepts be narrower than at least one of peripheral percepts. We have already seen that peripherality pre se probably does not decrease precision so if precision is decreased, it probably is due to withdrawal of attention. But empirical results suggest that withdrawal of attention does not decrease precision.
Conclusion: there is some reason to think that the phenomenology of perception is not grounded in its representational content.
Thus, for the perception of some properties, we have reason to believe that the representational content of perception neither grounds nor is grounded by the phenomenology of perception.
I argued that an attended .20o gap looks the same in respect of size as an unattended .23o gap. The comparative percept—the gaps looking the same—is illusory. But what about the percepts of each gap, considered separately? I argued that we would need a good reason to suppose that one but not the other is illusory and that the view that that both are illusory would undermine the notion of representational content altogether. I said that both are (or rather can be in normal circumstances) veridical. A similar point applies to the version of the experiments involving contrast in which an attended 22% patch looks the same in contrast as an unattended 28% patch. If the two patches look the same and if looking the same is a matter of sameness in representational content, and if the percepts are veridical, the size properties the patches are represented as having must be intervalic. And the interval—an index of precision—must be wide enough to encompass both patches. So the representational content has to have a precision range of 6%. And further considerations I mentioned suggest a range of 12%. The phenomenal precision principle says if percepts of 22% and 28% are phenomenally the same with one unattended in peripheral vision but determinately different when attended and foveal, then the attended and foveal percepts must have a narrower phenomenal precision than at least one of the peripheral percepts. The 22% and 28% patches do look determinately different if foveated and attended. So the attended and foveal percepts must have a narrower phenomenal precision than one of the peripheral percepts. The only way that this can happen on the representationist point of view is if one of the peripheral representational content is less precise than the foveal attended content. But experimental results that I cited suggest that may not be true. It may not be true of foveal vs peripheral vision independently of attention, and it may not be true for attention independently of foveal vs peripheral perception.
In the section on inhomogeneities of the visual field, I mentioned a route to the same conclusion based on introspection. And I will update that point to include attention. The more introspective route is this: it is natural to feel that the phenomenology of seeing the contrast between the lines and spaces on a piece of lined paper attentively and foveally differs in precision from seeing the same lines inattentively and peripherally. The foveal attentive percept seems more “crisp” than the inattentive peripheral percept. As we have seen, location is indeed represented more precisely but the same is not true for other properties such as hue or contrast. If this intuitive judgment is correct, there is introspective evidence for a discrepancy between the precision of phenomenology and the precision of representational content.
As I mentioned at the outset, the phenomenal precision principle needs more clarification and justification. It depends on notions of overlapping and of determinately different phenomenologies that are not as clear as one would like. My rationale is that if any advance in understanding of the phenomenology of perception is possible, it will have to start with underdeveloped ideas. I believe that there is enough in these ideas to give some credence to the conclusion. A second issue is whether the percepts that I say are determinately different in phenomenology really are.
The reader will have noticed that for the experimental results I have discussed it can often be difficult to figure out what aspects of the results concerned visual phenomenology and what aspects concern visual representation. As I mentioned earlier we have a real science of perception but very little science of the phenomenology of perception. If we are ever to turn what we know about perception into a scientific approach to the phenomenology of perception, we have no alternative but to start with some vague intuitive notions and proceed from there.
Although there are some loose ends, I think I have said enough to suggest a disconnect between the representational content of perception and what it is like to perceive.
Acknowledgements
I am grateful to Worth Boone, Tyler Burge, Marisa Carrasco, Jeremy Goodman, Eric Mandelbaum, John Morrison, Susanna Siegel, James Stazicker, Thomas Metzinger, Jennifer Windt and two anonymous reviewers for the Open MIND Project for comments on an earlier draft. And I am especially grateful to Jeremy Goodman and James Stazicker for discussion of these topics.